Improvement in vehicle-springs



UNITED STATES PATENT OEEIeE.

ALEXANDER W. HALL, OF NEI/V YORK, N. Y.

IMPROVEMENT IN VEHICLE-SPRINGS.

Specification forming part of Letters Patent No. 152,841, dated July 7,1874; application filed February 26, 1874.

To all vwho/1n it may concern Be it known that I, ALEXANDER W. HALL,ofthe cil y, county, and State of New York, have invented certainImprovements in Springs, of which the following is a specification:

M v invention relates to an improvement in the construction of springsfor vehicl es, whereby they in ay be made thinner and lighter withoutliability of buckling, crushing, or breaking, when compressed by theweight of the vehicle. The invention consists in an elliptic sprin g,formed of a strip of steel or other metal, made concave externally inits cross-section, and with a greater thickness at the edges than. inthe intervening `portions of its width.

In the accompanying drawing, Figure 1 is a central longitudinal verticalsection of my improved spring. Fig. 2 is a transverse seetion. Fig. 3 isalso a transverse section, showing a modification.

llhe spring is preferably made ot' a single strip of metal, and may beof elliptical or semielliptical form. f

Ihe drawing represents a spring, A, of elliptical form, composed of acontinuous strip of metal, bent or doubled, and having its ends weldedor otherwise joined together. In a spring constructed according to myinvention the portion between the ends of the ellipse is concave-convexin its cross-section, the coucave surface being outward. The concavityshould be greatest at the center of the spring, and diminish toward theends, which may be straight in their cross-section. The thickness of themetal is least at the longitudinal ccntral line of the spring, and mayincrease outward or toward the edges; but the thickness of metal isalways to be greatest at the edges, in consequence of which constructionthe edges of the spring, longitudinally, are capable of sustaining agreater amount of pressure than the intervening portion, for the weightof the vehicle pressing upon the spring has a tendency to straighten outthe edges longitudinally, and to press them toward eachothertransversely, so that the spring becomes stiffer as the pressureincreases, and the liability ot' buckling or crushing of the metal 'isless than it' thesprin g were of uniform thickness throughout.

rlhe enlargement or thickening of the edges may be carried to anydesired extent, and may bein any suitable form. Vhen made in the formshown in Fig. 3 it presents abroad bearin g-suri'aee for attachment tothe vehielc without increasing the width of the spring. The desired formmay be obtained by passing the strip or bar of' metal between rollers ofsuitable shape.

What I claim as new, and desire to secure by Letters Patent, is

An elliptic vehicle-spring, formed of a strip of metal concaveexternally in its cross-see tion, and having its edges thicker than theintervening portion, substantially as shown and described.

ALEX. W. HALL. Witnesses:

JNO. G. JoNEs, HENRY LEwrs.

